Spindle-stop mechanism



April 28, 1925.

J. J. THACHER SPINDLE STOP MECHANISM Filed June 18. 1923 ATTORNEY I I Il llllmuw Patented Apr. 28, 1925.

UNITED STATES PATENT OFFICE.

JOHN J. TEACHER, OF WETHERSFIELD, CONNECTICUT, ASSIGNOR TO PRATT WHIT-NEY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NE! JERSEY.

SPINDLE-STOP MECHANISM.

Application filed June 18, 1923. Serial No. 646,202.

T all whom it may concern:

Be it known that I, JOHN J. TEACHER, a citizen of the United States.residing at \Vethersfield, in the county of Hartford and State ofConnecticut, haveinvented certain new and useful Improvements inSpindle- Stop Mechanism, of whichthe following is a specification.

This invention relates to drilling machines and particularly to centerdrilling machines as illustrated in the accompanying drawing. In suclnmachinesthe operation.

to be performed is the drilling of a center holeinto the end face orfaces of a work 1 blank preparatory to mounting the same on thecentersof a lathe. Such hole must not only bedrilled at the center of the'blankbut must also be drilled to an exact and accurate. depth. This inventionrelates particularly to improved means for performing this latterfunction. Accordingly, the primary object of the. invention is toprovide improved means forlimiting the forward axial move ment of adrill spindle whereby the hole drilled thereby is accurately limited toa predetermined depth, such means also preferably being adjustable topermit drilling holes of varying depths. Another object of the inventionis to provide means mounted on the drill spindle sleeve and adapted inoperation to limit the forward drilling movement of the spindle byengaging against the work piece, such means also preferably beingadjustable to drill holes of varying depths.

Another object of the invention is to provide means mounted on the drillspindle sleeve and adapted in operation to limit the forward drillingmovement of the spindle by engaging against a shoulder on the headstockof the machine, such means also preferably being adjustable to drillholes of varying depths.

A further object of the invention is to provide means adapted to limitthe axialdrilling movement of a drill spindle either by engaging againstthe work piece being drilled or by engaging against a shoulder on theheadstock of the machine, such means comprising an element adapted to bemounted on the drill spindle sleeve in either of two positions, the samein one position limiting the drilling operation by engaging against thework piece and in the other position by engaging against the headstockof the machine.

lVith the above and other objects in View, my invention consists in thefeatures of construction and operation set forth in the followingspecification and illustrated in the accompanying drawing. In suchdrawing annexed hereto and forming a part of this specification, I haveshown one embodiment of -my invention, but it will be understood thatthe invention can be otherwise embodied and that the drawing is not tobe construed as defining or limiting the scope of the invention, theclaims appended to this specification being relied upon for thatpurpose.

Referring to the figures of the drawin Figure 1 is a fragmentary rearelevation of a center drilling machine embodying my invention. I

Fig. 2 is a fragmentar view of Fig. 1 but showing the drill spin les atthe limit of their drilling position.

Fig. -3 is a fragmentary cross sectional viewtaken on line 33 of Fig. 1.

Fig. 4 is a fragmentary side elevation of one drill spindle showing myimproved spindle stop means mounted in another position.

Fig. 5 is a view like Fi 4 but showing the drill spindle at the limlt ofits drilling position. i

Fig. 6 is an end view of Fig. 4.

In centering the opposite ends of a plurality of similar blankspreparatory to a turning operation either one of two conditions is to befulfilled. Either the countersunk centers are to be of predetermineddepth in each end regardless of whether the lengths of the blanks areslightly different, or, the distance between the countersunk ortions isto be exactly equal for all of the Blanks. In the first case, the endfaces of the blanks can be utilized as the stops'controlling the depthto which the drills may enter. In the second case, some fixed points onthe machine must be made use of as the stops. In the present invention,reversible stop members are provided which may be positioned so thatthey may operate in accordance with either requirement. In one case,they are positioned to abut against the end faces of the blanks and inthe other lot) case they are positioned to abut against the end face ofa depression formed in the headstocks carrying the drilling mechanisms.

In the accompanying drawing, I have illustrated a fragmentary portion ofthe automatic center drilling machine comprised in my copendingapplication, Serial No. 467,056, filed May 5, 1921. In such machine abed 1 supports respectively on opposite ends thereof a pair ofheadstocks 2 and 3. Within each headstock is an axially mov able sleeve4 rotatably supporting a drill spindle 5 therein. The spindles areadapted to be rotated from motors 6 through gearing 7.

The work blanks 8 to be drilled are automatically carried from amagazine 9 by a pair of carriers 10 to a pair of cooperating workengaging jaws 11. At this position the blank is centered and held inaxial alinement with and between the drill spindles during the drillingoperation. All of this mechanism is specifically illustrated anddescribed in my said copending application.

The drill spindles 5 are moved to engage the drills 5 with the workpiece as follows: Each sleeve 4 is provided with rack teeth, the rackteeth of one sleeve being engaged by a pinion 12 and the rack teeth ofthe other sleeve being engaged by a pinion 13. The pinion 13 is operatedby a second pinion 14. Connected with each pinion 12 and 14 is a bellcrank having arms 15 and 16, a spring pressed plunger 17 being mountedin each arm 16. A loosely mounted lever 18 extends between the arms 15and 16 and the free ends of such levers are connected to an element 19by means of links 20. It will be noted that movement of the element 19in the direction of the arrow in Fig. 1 rotates the pinions 12 and 13 indirections to move the spindles inwardly to the work.

The forward end of each sleeve 4 is provided with a collar 21 preferablyintegral therewith. The outer end of a radially projecting portion ofthis collar has an openlng for receiving the shank 22 of my improvedspindle stop member. A set screw 23 threaded into the collar is adaptedto secure the shank in the collar. One end of theshank is provided witha head comprising a bifurcated portion 24 and a relatively short portion25 directly opposite the bi- -furcated portion.

In Figs. 1, 2 and 3 I have illustrated the shank 22 as so mounted in thecollar that the head extends forwardly and the bifurcated portion 24extends inwardl about the drill 5. A blank is fed forwarc to theposition shown in Fig. 3 while the drill spindles are in the positionshown in Fig. 1. The element 19 is then moved to the left, whichoperates to engage the drills with the work. As the drills are movedforwardly under the action of the element 19, the bifurcated portions 24of the heads come in contact with the work and stop further movement ofthe drills therein. This position of the parts is shown in Fig. 2. Itwill be understood that any further movement of the element 19 beyondthis limit is taken up at lost motion b the spring pressed plungers 17.It will urthermore be understood that the depth of drilling may bewaried by adjusting the shanks 22 in the collar. 21.

Each headstock 2 and 3 is provided with a recess 26 therein providing ashoulder 27 at the forward end thereof. In Figs..4, 5 and 6 I haveillustrated the shank 22 as so mounted in the collar that the headextends rearwardly and the relatively short portion 25 thereof extendsinto the recess 26. In Fig. 4 the spindle is shown in the rearwardposition and in Fig. 5 the spindle is shown at the limit of its forwardmovement. In the latter position it will be noted that the head portion25 has engaged against the shoulder 27 and stopped the forward movementof the spindle. The depth of drilling is thus definitely limited asillustrated in Fig. 5. This depth can be varied by adjusting the shank22 longitudinally in the collar 21.

It is believed that the construction and operation of my improvedmechanism will be clear from the above description. The spindle stopmeans may function in either of the two ways illustrated and the depthof drilling in either case may be easily and accurately adjusted bymeans of the set screw 23. 4

\Vhat I claim is:

1. In a drilling machine, the combination of a headstock, an axiallymovable sleeve mounted therein, a drill spindle mounted in the sleeve,and means to limit the forward movement of the sleeve and spindle byengaging either against the work piece or against the headstock.

2. In a drilling machine, the combination of a headstock, an axiallymovable sleeve mounted therein, a drill spindle mounted in the sleeve,means adapted to limit the forward movement of the sleeve and spindle byengaging either against the work piece or against the headstock, andmeans for adjusting the first said means whereby to vary the said limitof movement.

3. In a drilling machine, the combination of a headstock, an axiallymovable sleeve mounted therein, a drill spindle mounted in the sleeve, acollar on the sleeve, and an element adapted to be mounted on the collarin either of two positions, the element in one position being adapted tolimit the forward movement of the sleeve and spindle in'drilling byengaging against the work piece and in the other position being adaptedto limit the same by engaging against the headstock.

4. In a drilling machine, the combination of a headstock, an axiallymovable sleeve mounted therein, a drill spindle mounted in the sleeve, acollar on the sleeve, an element adapted to be mounted on the collar ineither of two positions, the element in one position "being adapted tolimit the forward move ment of the sleeve and spindle in drilling byengaging against the work piece and in the other position being adaptedto limit the .same by engaging against the headstock,

on the sleeve, an element comprising a shank with a head thereon, theshank being adjustahlymountable in the collar with the head extendingrearwardly and into the recess or forwardly and inwardly to a positionadjacent the spindle axis, the element in'the first position beingadapted to limit the forward movement of the sleeve and spindle byengaging ainst the said shoulder and being adapte d in the latterposition to limit the same by engaging against the work piece, and meanspermitting axial adjustment of the shank in the collar.

6. In a center drilling machine, the combination of a pair of axiallyspaced headstocks, an axially movable sleeve mounted in each headstock,a drill spindle mounted in each sleeve, means for supporting a workblank in endwise relation between the drill spindles, and mansadjustably mounted on the sleeves and adapted to limit the forwarddrilling movement .of the sleeves and spindles either by engagingagainst the ends of the blank or by engaging against abutments on theheadstocks.

In testimony whereof, I hereto aflix my signature.

- 'JOHN J. THAOHER.

